Les prototypes d'avions US (US X planes)

Citation :

F-18 HARV Achievements:
The F-18 HARV demonstrated stabilized flight at angles of attack between 65 and 70 degrees using thrust vectoring vanes

F-18 HARV Specifications:
Primary Function: experimental - High Angle-of-Attack (Alpha) Research Vehicle
Contractor: McDonnell Douglas
Crew: One
Unit Cost: N/A
Powerplant
Two General Electric F404-GE-400 turbofan engines, each producing 16,000 pounds of thrust in afterburner
Dimensions
Length: 56 ft
Wingspan: 37 ft, 5 in
Height: 10 ft, 6 in -- at canopy
Weights
Empty: N/A
Gross Weight: 31,980 lb -- phase I; 36,099 lb phase II and III
Performance
Speed: limited to 170 mph
Ceiling: N/A
Range: N/A
Armament
N/A

Photos:




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F-15 ACTIVE

Citation :

F-15 ACTIVE Achievements:
The F-15 ACTIVE demonstrated the first supersonic yaw-vectoring flight
The F-15 ACTIVE demonstrated the first pitch and yaw thrust vectoring at speeds up to Mach 2
The F-15 ACTIVE was the first two-seat F-15 built by McDonnell Douglas


F-15 ACTIVE Specifications:
Primary Function: experimental - Advanced Control Technology for Integrated Vehicles
Contractor: McDonnell Douglas
Crew: Two
Unit Cost: N/A
Powerplant
Two higher-thrust version Pratt & Whitney F100-PW-229 engines (with newly developed axisymmetric thrust-vectoring engine exhaust nozzles) rated at 29,000 lbs. of thrust each at full power
Dimensions
Length: 63.7 ft, excluding flight test nose boom
Wingspan: 42.8 ft
Canard span: 25.6 ft
Height: 18.5 ft - F-15
Weights
Empty: 35,000 lb
TOW: 47,000 lb
Performance
Speed: Mach 2.0 (speeds limited to Mach 1.2)
Ceiling: 60,000 feet
Range: N/A
Armament
N/A

Photos:







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Citation :

X-43 Hyper-X Achievements:
The X-43 is currently the fastest aircraft in the world.

X-43 Hyper-X Specifications:
Primary Function: Experimental hypersonic aircraft
Contractor: Boeing
Crew: None
Unit Cost: N/A
Powerplant
One scramjet engine
Dimensions
Length: 14 feet, 4 in
[b]Wingspan: 5 feet
Height:[/b] 2 feet, 2 in
Weights
Empty: N/A
Maximum: 3,000 lb
Performance
Speed: Mach 9.6 (~7,000 mph)
Ceiling: 95,000+ ft
Range: N/A
Armament
N/A

Photos:



www.globalaircraft.org

Citation :

X-45 UCAV Achievements:
No known major achievements

X-45 UCAV Specifications:
Primary Function: Joint Unmanned Combat Air System demonstrator
Contractor: Boeing
Crew: None
Unit Cost: $10 - $15 million
Powerplant
N/A
Dimensions (X-45C)
Length: 39 feet
Wingspan: 49 feet
Height: N/A
Weights
Empty: N/A
Maximum Payload: 4,500 lb
Performance
Speed: Mach 0.85
Ceiling: 40,000 ft
Range: 1,300 nm
Armament
Various smart bombs

Photos:






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Citation :

F-16 AFTI Achievements:
Numerous flight avionics technologies advancements (Automatic Ground Collision Avoidance System, Real Time Kill Recognition, close air support and battlefield air interdiction, voice control system, etc.)


F-16 AFTI Specifications:
F-16 AFTI based on F-16A (Serial #75-0750) -- F-16A stats shown
Primary Function: experimental - Advanced Fighter Technology Integration
Contractor: Lockheed (General Dynamics)
Crew: One
Unit Cost: N/A
Powerplant
One Pratt & Whitney F100-PW-200 rated at 23,830 lb. thrust with afterburner
Dimensions
Length: 49 ft, 6 in
Wingspan: 32 ft, 10 in
Height: 16 ft, 6 in
Weights
Empty: N/A
Loaded: 29,896 lb
Performance
Speed: 1,345 mph
Ceiling: 55,000 ft
Range: 1,407 miles
Armament
N/A

Photos:




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F-16XL

Citation :

F-16XL Specifications:

Primary Function: experimental - Laminar Flow Research Aircraft
Contractor: General Dynamics Corp.
Crew: One
Unit Cost: N/A
Powerplant
Pratt and Whitney 100-PW-100 engine (with afterburner), rated at 23,830 lb thrust
Dimensions
Length: 54.2 ft (16.52 m)
Wingspan: 34.3 ft (10.45 m)
Height: 17.7 ft (5.39 m)
Weights
Empty: N/A
Max. Weight: 48,000 lb (17,915.60 kg)
Performance
Speed: Mach 1.8 (1,260 mph)
Ceiling: 50,000 ft
Range: 2,850 miles
Armament
N/A

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Citation :

X-29 FSW Achievements:
Studies from the X-29 showed that forward swept wings, coupled with movable canards, gave pilots excellent control response.

X-29 FSW Specifications:
Primary Function: Experimental Aircraft
Contractor: Grumman
Crew: One
Unit Cost: N/A
Powerplant
One General Electric F404-GE-400 at 16,000 lb of thrust
Dimensions
Length: 48.1 feet
Wingspan: 27.2 feet
Height: 14 feet
Weights
Empty: 13,600 lb
Maximum Takeoff: 17,600 lb
Performance
Speed: Mach 1.6 (1,120mph)
Ceiling: 50,000 feet
Range: N/A
Armament
N/A

X-29 FSW Background:
Two X-29 Forward Swept Wing aircraft were built as advanced concepts and technology demonstrators. The test program was conducted from 1984 to 1992 and provided an ample supply of engineering information which can be used for the design and development of future aircraft.

The X-29 featured forward swept wings planted well in the back of the fuselage, and canards to control pitch and acted as horizontal stabilizers. This new wing design proved exceptional maneuverability, a light structure, and supersonic performance. The test results of this design showed excellent control response at angles of attack up to 45 degrees. During its life, the X-29 aircraft were flown on 422 research missions. Including non-research flights, the X-29 aircraft flew 436 missions total.

Photos:


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Citation :

X-31 EFMD Specifications
Primary Function: Experimental Aircraft
Contractor: Rockwell, North American Aircraft, Deutsche Aerospace
Crew: One
Unit Cost: N/A
Powerplant
One General Electic F404-GE-400 at 16,000 lb of thrust
Dimensions
Length: 43ft 3in
Wingspan: 23ft 8in
Height: 14ft 5in
Weights
Empty: 10,212 lb
Maximum Takeoff: 16,100 lb -- gross
Performance
Speed: More than mach 1.28
Ceiling: over 40,000 ft
Range: N/A
Armament
N/A

X-31 EFMD Achievements:
The X-31 provided information for proceeding with the designs of the next generation highly maneuverable fighters.

X-31 EFMD Features:
Three thrust vectoring paddles made of graphite epoxy and mounted on the X-31's aft fuselage were directed into the engine exhaust plume to provide control in pitch (up and down) and yaw (right and left) to improve maneuverability. The paddles sustained temperatures of up to 1,500 degrees centigrade for extended periods of time. In addition, the X-31s was configured with movable forward canards, wing control surfaces, and fixed aft strakes. The canards are small wing-like structures located just aft of the nose, set on a line parallel to the wing between the nose and the leading edge of the wing.

X-31 EFMD Background:
The X-31 flight test program was conducted by an international test organization (ITO) managed by the Advanced Research Projects Office (ARPA), known as the Defense Advanced Research Projects Office (DARPA) before March 1993. The ITO included the U.S. Navy and U.S. Air Force, Rockwell Aerospace, the Federal Republic of Germany, Daimler-Benz (formerly Messerschmitt-Bolkow-Blohm and Deutsche Aerospace), and NASA. Gary Trippensee was the ITO director and NASA Project Manager. Pilots came from participating organizations.

The X-31 program demonstrated the value of using thrust vectoring (directing engine exhaust flow) coupled with advanced flight control systems, to provide controlled flight to very high angles of attack. The result was a significant advantage over conventional fighters in a close-in combat situation.

Photos:






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Citation :

F-18 High Alpha Research Vehicle (HARV)

Project Summary

NASA's Dryden Flight Research Center, Edwards, Calif., used an F-18 Hornet fighter aircraft as its High Angle-of-Attack (Alpha) Research Vehicle (HARV) in a three-phased flight research program lasting from April 1987 until September 1996.The aircraft completed 385 research flights and demonstrated stabilized flight at angles of attack between 65 and 70 degrees using thrust vectoring vanes, a research flight control system, and forebody strakes (hinged structures on the forward side of the fuselage to provide control by interacting with vortices, generated at high angles of attack, to create side forces).


Phase One

The first phase of "high alpha" flights began in April 1987 and lasted through 1989. It consisted of 101 research flights in the specially instrumented F-18 at angles of attack as high as 55 degrees. During this phase, there were no external modifications to the aircraft, but technicians equipped it with extensive instrumentation. NASA research pilot Einar Enevoldson made the first (functional check) flight on April 2, 1987, and three succeeding flights before turning the piloting duties over to NASA research pilots Bill Dana and Ed Schneider. The purpose of this phase was to obtain experience with aerodynamic measurements at high angles of attack and to develop the flight research techniques needed for this measurement.

Researchers conducted visual studies of the airflow over various parts of the aircraft. Special tracer smoke was released through small ports just forward of the leading edge extensions near the nose; on-board video and still cameras captured images of the smoke as it followed airflow patterns around the aircraft. Also photographed in the airflow were short pieces of yarn (tufts) taped on the aircraft and anti-freeze with dye in it, released onto the aircraft surfaces from hundreds of small orifices around the vehicle's nose.

Researchers used the film and videotape images of the airflow patterns from the smoke, dye, and tufts for a comparison with computer and wind tunnel predictions. Additional data that they obtained included air pressures recorded by sensors located in a 360-degree pattern around the nose and at other locations on the aircraft. Researchers paid particular attention to the location of strong vortices (masses of air in circular motion) that formed off the forebody and wing-body-strake (leading-edge extension or LEX) at high angles of attack and their role in inducing tail buffeting (beating by unsteady flow, gusts, etc.).


Phase Two

Phase Two flights examined the benefits of using vectored thrust to achieve greater maneuverability and control at high angles of attack while continuing the correlation of flight data with wind-tunnel and computational fluid dynamics (CFD) data begun in Phase One. The initial portion of the Phase Two flight program was completed in January 1993.

Phase Two featured major hardware and software modifications to the HARV – a multiaxis thrust-vectoring control system featuring vanes attached to the aft end of the aircraft and a research flight control system. Three paddle-like vanes, made of Inconel®1 metal (a nickel alloy containing chromium and iron that is heat resistant), were mounted around each engine's exhaust. They provided both pitch (up and down) and yaw (right and left) forces to enhance maneuverability when the aerodynamic controls were either unusable or less effective than desired. The engines had the divergent portion of the exhaust nozzles removed to shorten the distance the vanes had to be cantilevered by about two feet. The subsonic performance of the engines, including afterburning, was largely unaffected by the modifications, but supersonic flight was no longer possible – a penalty unique to this experimental project. The thrust vectoring control system added 2,200 pounds to the total weight of the aircraft. In addition, the inclusion of a spin parachute for safety plus an emergency power system and ballast added a further weight penalty of 1,500 pounds. The HARV also carried 419 pounds of other equipment and wiring not directly associated with the thrust-vector-control system.

The research flights began in July 1991 using the thrust vectoring system for control. The system could deflect the exhaust flow from the two turbofan engines to provide enhanced maneuverability and control in areas where conventional aerodynamic controls are ineffective. (These controls included ailerons, rudders, stabilators [stabilizers + elevators – all-movable horizontal stabilizers in the tail area], and leading-edge flaps.) The system resulted in significantly increased maneuverability at moderate angles of attack and some degree of control at angles of attack up to roughly 70 degrees. It also allowed researchers to collect a greater amount of data by remaining at high angles of attack longer than they could have done without it.

The modified flight control computers used a PACE 1750A computer and specially written flight control laws to provide the research flight control capability. These laws commanded the optimum combination of aerodynamic control and vectored thrust to satisfy pilot demand. Program engineers integrated all controls into these flight control laws. The pilot used standard cockpit controls and no special pilot action was required after the system was engaged in flight. In addition to the research flight control computers, pilots also used the original F-18 flight control system both as a backup to the research system and to perform take-offs and landings.

Dryden research pilots Bill Dana and Ed Schneider completed the envelope expansion flights in February 1992. Demonstrated capabilities included stable flight at approximately 70 degrees angle of attack (previous maximum was 55 degrees) and rolling at high rates at 65 degrees angle of attack. Controlled rolling would have been nearly impossible above 35 degrees without vectoring.

Between January 1993 and January 1994 the aircraft was modified with a sophisticated engine inlet pressure measurements system between the inlet entrance and the engine face. This information provided unprecedented understanding of what happens to engine airflow under extreme maneuver conditions. Flights resumed in January 1994 and continued through June 1994, with Ed Schneider and Jim Smolka as the Dryden research pilots, joined for short periods by U.S. Navy pilots. In Phase Two there were a total of 193 flights, including some transition flights to Phase Three.


Phase Three

The Phase Three effort began in March 1995 to evaluate moveable strakes on both sides of the aircraft's nose to provide yaw control at high angles of attack where conventional rudders became ineffective. These strakes, 4 feet long and 6 inches wide, were hinged on one side and mounted to the forward sides of the fuselage. At low angles of attack, they were folded flush against the aircraft skin. At higher angles of attack, they were extended to interact with the strong vortices generated along the nose and thereby produce large side forces for control. Wind tunnel tests indicated strakes could be as effective at high angles of attack as rudders are at lower angles. Flights with active moveable strakes began in July 1995. The availability of the strakes enabled pilots to employ three separate flight modes. One used thrust vectoring alone. Another used thrust vectoring for longitudinal (pitch) control and a blend of thrust vectoring and strakes for lateral (side-to-side) control. A third mode used thrust vectoring solely for longitudinal control, with strakes alone for controlling lateral motion. These three options were a unique feature of the HARV project. They afforded a great deal of flexibility in research into control power requirements at high angles of attack. They were also a means of achieving detailed investigation of handling qualities at high angles of attack.

The strake project concluded in September 1996 with flight 385 of the HARV program. It yielded a great deal of information about the operation of nose strakes, which were effective in providing control above 35 degrees angle of attack. Phase Three included 109 flights. Besides Schneider and Smolka, the research pilots included Mark Stucky from Dryden, Phil Brown from Langley, and a number of guest pilots from the U.S. Navy and Marine Corps, the Canadian Air Force, the (British) Royal Air Force, McDonnell Douglas, CalSpan and NASA Dryden.

http://www.nasa.gov/centers/dryden/history/pastprojects/HARV/index.html

de droite à gauche F-16 XL (monoplace), F-16 AFTI, F-16 A et F-16 XL (biplace):




de droite à gauche F-16 AFTI, F-16 XL, F-16 A:




The AFTI F-16 in its final configuration, flying in the vicinity of Edwards Air Force Base, California. During this phase, the two forward infrared turrets were added ahead of the cockpit, the chin canards were removed, and the aircraft was repainted in a standard Air Force scheme. A fuel drop tank is visible below the wing.

Citation :

Le Boeing X-32 est un avion multirôle expérimental construit dans le cadre du Joint Strike Fighter Program lancé par l'agence américaine de recherches sur les projets de défense (DARPA) en 1990.

Le X-32A a effectué son premier vol de l'usine de Palmdale en Californie à la base aérienne d'Edwards appartenant à l'USAF le 18 septembre 2000.

Trois versions étaient prévues dont une à décollage vertical, le X-32B.

L'aéronef était en concurrence avec le Lockheed F-35 Lightning II (projet X-35) dans le but de remplacer l'ensemble des avions légers de combats et d'attaque du Département de la Défense des États-Unis. Il était alors question de remplacer les General Dynamics F-16 Falcon, McDonnell Douglas F/A-18 Hornet et autres Short Take Off Vertical Landing (aéronefs à décollage court et à atterrissage vertical) AV-8 Harrier II.

Le 26 octobre 2001, c'est le projet X-35 concurrent qui lui est préféré.

http://fr.wikipedia.org/wiki/Boeing_X-32

Citation :

L’aile volante X-48B de Boeing réussit ses essais

Par Jean Etienne, Futura-Sciences

L'aile volante, c'est-à-dire un avion sans fuselage, joue l'éternel retour. Ses avantages sont connus et indéniables. Sans fuselage, le poids et la traînée sont plus faibles et la stabilité peut être obtenue moyennant quelques astuces. Boeing et la Nasa planchent actuellement, avec succès, sur un prototype.

Après une première saison d’essais en vol pleinement réussis en 2007, le X-48B élaboré par Boeing en partenariat avec la Nasa vient d’entamer une deuxième série de tests pilotés au Dryden Flight Research Center (Californie).

Piloté n’est pas tout à fait le mot exact, puisque ce prototype est en réalité un modèle réduit à l’échelle 1/12 commandé depuis le sol. Des caméras installées sur l’appareil remplacent les yeux du pilote, qui se trouve dans une salle ressemblant à un simulateur de vol. Même dans cette configuration, l’actuel X-48B accuse tout de même 250 kg pour une envergure de 6,40 mètres.

Le concept de l’aile volante n’est pas nouveau mais il n’a jamais cessé de soulever de nombreux problèmes de stabilité en lacet (mouvement autour d'un axe, à cause de l’absence de dérive verticale. Le bombardier furtif B2-A Spirit est bien une aile volante, mais il ne pourrait voler si ses commandes n’étaient pas assistées en permanence par ordinateur.

Cependant, la Nasa estime que cette solution finira par s’imposer tant dans le civil que dans le domaine militaire. L’aile volante présente en effet des avantages connus. A masse égale, la portance est plus élevée puisqu'il n'y a pas de fuselage, un corps pesant sans valeur aérodynamique sur un avion traditionnel. La traînée aérodynamique est significativement réduite et on obtient donc une consommation moindre. De plus, sur le modèle étudié par la Nasa et Boeing, la disposition des moteurs au-dessus des ailes le rendra particulièrement silencieux.

Des essais à vitesses plus élevées

Lors des premiers vols effectués en 2007 sur la base d’Edwards en Californie, l’appareil – le X-48B Ship 1 – avait atteint 2.500 mètres d’altitude. Les tests avaient surtout exploré le domaine des basses vitesses. Les volets (surfaces mobiles sur les bords de fuite) étaient restés en position basse. Cette configuration volets sortis est celle du décollage ou de l’atterrissage. Elle garantit une portance plus élevée, une traînée accrue et une vitesse maximale réduite à environ 110 km/h. Dans la série de vols qui vient de débuter, les volets du second appareil – le X-48B Schip 2 – sont rentrés (configuration lisse), ce qui permettra de voler à 140 km/h en croisière, avec un maximum théorique de 220 km/h, et d’atteindre une altitude plus élevée.

Le X-48B Ship 2 en vol au-dessus d’Edwards le 4 avril 2008. Crédit Nasa

Si la première phase d’essais comprenait 11 vols, la deuxième en comprendra au moins 8. Six phases sont prévues, durant desquelles le niveau de risque sera progressivement augmenté. Au cours de la sixième phase, les paramètres du logiciel de contrôle de vol seront peu à peu modifiés, réduisant la marge de sécurité qui empêche, notamment, l’avion de se mettre en décrochage.

Le programme de recherches du X-48B est dirigé par Phantom Works, une unité de R&D de Boeing travaillant sur des solutions innovantes en matière aéronautique et spatiale. Les prototypes ont été construits par Cranfield Aerospace, au Royaume-Uni, selon les spécifications de Boeing.

Le X-48B au cours de tests en soufflerie au Dryden Flight Research Center de la Nasa. Crédit Nasa

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